Integrated circuits (“ICs”) are incorporated into many electronic devices. IC packaging has evolved such that multiple ICs may be vertically joined together in so-called three-dimensional (“3D”) packages in order to save horizontal area on a printed circuit board (“PCB”). These 3D IC packages may use an interposer, which may be formed from a semiconductor material such as silicon, for coupling one or more dies to a PCB. Interposers affect the operating characteristics of the ICs that are bonded or otherwise coupled to the interposer due to the resistance and capacitance (“RC”) of the semiconductor substrate.